Being able to configure slaves to be crash-safe is one of the major improvements of MySQL 5.6 with regards to replication. However we noticed confusion on how to enable this feature correctly, so let’s clarify how it should be done.

In short

1. Stop MySQL on slave
2. Add relay_log_info_repository = TABLE and relay_log_recovery = ON in my.cnf
3. Restart MySQL and relax

The gory details

To fully understand why you should change the above settings if you want crash-safe slaves, let’s first look at the reasons why replication can break when a slave crashes.

On a slave, replication involves 2 threads: the IO thread which copies the binary log of the master to a local copy called the relay log and the SQL thread which then executes the queries written in the relay log. The current position of each thread is stored in a file: master.info for the IO thread …

So we all know that when troubleshooting MySQL crashes or any other processes in that regard, we simply enable core files to be dumped when the appropriate signal it triggered. To get the best results, we’d set the core file size limit everywhere to unlimited and be done with it, but what if you want to limit that to a certain size? I stumble to a small confusion lately when doing this for MySQL, so let me share quickly.

First, for MySQL, mysqld_safe would use ulimit to set the core-file-size value you pass to it. Now remember according to the manual, this value should be in blocks (some documentation says its in chunks of 1024 bytes). However, according to my experience on CentOS 6, this is the physical block size of the device where your core_pattern is pointed to.

[root@centos6 ~]# ulimit -a
...
core file size          (blocks, -c) 0

[root@centos6 ~]# cat /proc/sys/kernel/core_pattern
/var/tmp/core

[root@centos6 ~]# blockdev …

Join me Wednesday, September 18 at 10 a.m. PDT for an hour-long webinar where I will introduce the basic concepts behind column store technology. The webinar’s title is: “Introduction to open source column stores.”

What will be discussed?

This webinar will talk about Infobright, LucidDB, MonetDB, Hadoop (Impala) and other column stores

• I will compare features between major column stores (both open and closed source).
• Some benchmarks will be used to demonstrate the basic performance characteristics of the open source column stores.
• There will be a question and answer session to ask me anything you like about column stores (you can also ask in the …

Want to prove your expertise with MySQL? Why not get certified.

Oracle has just announced the release of the new MySQL Certification Path including the:

• Oracle Certified Professional, MySQL 5.6 Developer (OCP)
• Oracle Certified Professional, MySQL 5.6 Database Administrator (OCP)

You can register for these certification exams from today. Learn more about these certifications on the Oracle University blog.

Successful candidates will require a strong MySQL experience. Although …

There are multiple ways to backup a MySQL database. Some are more painful than others. In this two part blog we are going to discuss why the new hot backup system in TokuDB is special amidst the existing solutions. First let’s look at existing backup solutions for MySQL and InnoDB.

Let’s start with the most obvious, and possibly painful, way to make a backup of MySQL: a manual copy of the MySQL data directory.

Coarse Copy

The copying itself isn’t the painful part; any DBA worth their salt can copy a directory. Guaranteeing what comes out the other end, however, is difficult. In other words, what will the state of each table in each database look like when the backup is complete? It turns out, without additional help, we don’t know!

If you think about the dynamic state of a database, and the serial copying of the same database files from one space to another, some questions may start to …

Join Continuent and our customers Modernizing Medicine and Marketo to learn how to run business-critical MySQL applications in the cloud or on-premises. Modernizing Medicine is a fast-growing SaaS company, offering electronic medical records management solution. Matthew Lang, Sr. Site Reliability Engineer at Modernizing Medicine, describes how Modernizing Medicine serves thousands of customers

I’m a big fan of the MySQL command line tool ie the default text client modestly named: mysql. I use it everyday because you can do almost everything with it (DML, DDL, DCL, administrative tasks,...).

It has many options including generate xml or html output.

$ mysql --help | grep "\--html" -H, --html Produce HTML output.

On Tuesday Sept.10 I went to PHP TechTalks with Rasmus Lerdorf, Sebastian Bergmann, and Stig Bakken. Great initiative by Stig Bakken @ Zedge. The TechTalks focused on new features and best practices and for PHP 5.4 and 5.5.
Great feeling of going to the roots of LAMP and MySQL. Thanks for the invite Stig!

(For more have a look at https://zedgetechtalksphp.eventbrite.com/).

It is our great pleasure to announce that Harrison Fisk will deliver a "MySQL at Facebook" keynote at MySQL Connect!

Our keynote lineup is now as follows:

Saturday, September 21, 9:00 a.m.–10:00 a.m.
The State of The Dolphin

Join Edward Screven, Oracle’s Chief Corporate Architect, and Tomas Ulin, Vice President of MySQL engineering, for the State of the Dolphin keynote address. Learn about Oracle’s MySQL strategy as well as the latest innovations and plans for MySQL.

10:00 a.m.–10:20 a.m.
MySQL At Facebook

MySQL has come a long way at Facebook, now hosting one of the world's largest online data set. Don't miss Harrison's exciting keynote about MySQL at …

While we are working hard on the final push of Percona Server 5.6 GA (I know that many people are waiting on this, but stay with us – we want to ensure that we have a quality release with great performance), I decided to make an experimental build of Percona Server 5.6 with the TokuDB engine.

It’s available here: http://www.percona.com/downloads/TESTING/Percona-TokuDB/.

If you are interested, please test it and provide us with feedback. If things look good, in couple months we may release an official Percona Server 5.6 with TokuDB.

The post …